abt-199 and pevonedistat

Conventional chemotherapy with cytarabine and anthracycline (often referred to as "7+3") has been used for many years in the treatment of acute myeloid leukemia (AML). Despite meaningful advances in areas of supportive care and transplantation, little progress has been made in developing new chemotherapy options. In 2018, The Food and Drug Administration (FDA) of the US approved several novel agents for AML treatment as follows: ivosidenib, an inhibitor of isocitrate dehydrogenase-1; venetoclax, a potent inhibitor of bcl2; and glasdegib, an inhibitor of hedgehog signaling pathway. Moreover, clinical trials of alvocidib (flavopiridol), an inhibitor of the CDK9, pevonedistat, an inhibitor of NEDD8, and APR-246, a reactivator of mutant p53, are in progress. These agents will either be incorporated into the conventional 7+3 regimen or combined with hypomethylating agents to improve the outcome of AML therapy, and the results will guide the next stage of precision medicine in the treatment of AML.

Topics: Benzimidazoles; Bridged Bicyclo Compounds, Heterocyclic; Cyclopentanes; Drug Approval; Flavonoids; Glycine; Humans; Leukemia, Myeloid, Acute; Molecular Targeted Therapy; Phenylurea Compounds; Piperidines; Pyridines; Pyrimidines; Sulfonamides; United States; United States Food and Drug Administration

Topics: Aged, 80 and over; Aniline Compounds; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Bridged Bicyclo Compounds, Heterocyclic; Cyclopentanes; Disease-Free Survival; Female; Glycine; Humans; Leukemia, Myeloid, Acute; Male; Pyrazines; Pyridines; Pyrimidines; Retrospective Studies; Sulfonamides; Survival Rate

Dysregulation of apoptotic machinery is one mechanism by which acute myeloid leukemia (AML) acquires a clonal survival advantage. B-cell lymphoma protein-2 (BCL2) overexpression is a common feature in hematologic malignancies. The selective BCL2 inhibitor, venetoclax (VEN) is used in combination with azacitidine (AZA), a DNAmethyltransferase inhibitor (DNMTi), to treat patients with AML. Despite promising response rates to VEN/AZA, resistance to the agent is common. One identified mechanism of resistance is the upregulation of myeloid cell leukemia-1 protein (MCL1). Pevonedistat (PEV), a novel agent that inhibits NEDD8-activating enzyme, and AZA both upregulate NOXA (PMAIP1), a BCL2 family protein that competes with effector molecules at the BH3 binding site of MCL1. We demonstrate that PEV/AZA combination induces NOXA to a greater degree than either PEV or AZA alone, which enhances VEN-mediated apoptosis. Herein, using AML cell lines and primary AML patient samples ex vivo, including in cells with genetic alterations linked to treatment resistance, we demonstrate robust activity of the PEV/VEN/AZA triplet. These findings were corroborated in preclinical systemic engrafted models of AML. Collectively, these results provide rational for combining PEV/VEN/AZA as a novel therapeutic approach in overcoming AML resistance in current therapies.

Topics: Azacitidine; Bridged Bicyclo Compounds, Heterocyclic; Cyclopentanes; Humans; Leukemia, Myeloid, Acute; Pyrimidines; Sulfonamides

MLN4924 (pevonedistat), an inhibitor of the Nedd8 activating enzyme (NAE), has exhibited promising clinical activity in acute myelogenous leukemia (AML). Here we demonstrate that MLN4924 induces apoptosis in AML cell lines and clinical samples via a mechanism distinct from those observed in other malignancies. Inactivation of E3 cullin ring ligases (CRLs) through NAE inhibition causes accumulation of the CRL substrate c-Myc, which transactivates the PMAIP1 gene encoding Noxa, leading to increased Noxa protein, Bax and Bak activation, and subsequent apoptotic changes. Importantly, c-Myc knockdown diminishes Noxa induction; and Noxa siRNA diminishes MLN4924-induced killing. Because Noxa also neutralizes Mcl-1, an anti-apoptotic Bcl-2 paralog often upregulated in resistant AML, further experiments have examined the effect of combining MLN4924 with BH3 mimetics that target other anti-apoptotic proteins. In combination with ABT-199 or ABT-263 (navitoclax), MLN4924 exerts a synergistic cytotoxic effect. Collectively, these results provide new insight into MLN4924-induced engagement of the apoptotic machinery that could help guide further exploration of MLN4924 for AML.

Topics: Antineoplastic Agents; Apoptosis; Bridged Bicyclo Compounds, Heterocyclic; Cell Line, Tumor; Cyclopentanes; Drug Synergism; HL-60 Cells; Humans; Leukemia, Myeloid, Acute; Myeloid Cell Leukemia Sequence 1 Protein; Proto-Oncogene Proteins c-bcl-2; Proto-Oncogene Proteins c-myc; Pyrimidines; RNA Interference; RNA, Small Interfering; Sulfonamides; Up-Regulation